With the proliferation of mobile electronic devices, many wireless devices are necessarily powered by batteries. For example, devices in wireless local area network (WLAN) or wireless personal area network (WPAN) mesh networks are battery powered. In such networks, the number of nodes may be very large. One of the technical challenges for sustaining wireless mesh networks is maintaining batteries for hundreds, or even thousands, of nodes in a network. Current battery technology requires the battery of a wireless sensor node to be changed every several days or at most every several months. This is an obstacle for widespread adoption of wireless mesh networks.